Most of its work to determine the scope of the regional threat has concentrated on Berks County, where high levels of radon first were found to present a direct health hazard to people.

Yesterday DER Press Secretary Bruce Dallas said East Penn is the only school district in Lehigh County that has been checked for radon by the state.

But DER also has taken initial air samples, and placed radon detectors, in the Southern Lehigh School District.

Dallas said other districts in thecounty that may have radon concerns will have to wait until at least the end of summer before any more testing of school buildings is done by DER.

He also said schools will be tested before homes are tested.

The press secretary said safe radon levels were measured in all schools at East Penn. But a school official indicated that is only a tentative result. Devices to test radon levels over a longer period have been placed in all 12 of the district's schools by the state.

DER personnel who completed initial testing in East Penn schools yesterday assured school officials that if their original air monitoring checks don't indicate a problem, it also is unlikely the detectors will find one.

Radon is a naturally occurring gas that can build up to unhealthy concentrations inside buildings.

East Penn, which has about 5,800 students, expects to get more definitive results from DER by July. Southern Lehigh, which has about 2,600 students, also hopes to get radon detector results from DER by the end of that month.

Yesterday Southern Lehigh schools' superintendent Michael Greene said DER gave his district no tentative results. Greene said last week he informed all parents in the district about the radon testing in the seven buildings of Southern Lehigh.

Initial radon air sampling was done May 14 in Southern Lehigh and May 23 in East Penn.

But yesterday the state returned to Vera Cruz School in East Penn for retesting, because initial results showed there might be a problem in that building. A school district official said DER gave Vera Cruz "a clean bill of health" after it did the retesting. Dallas said the follow-up testing that showed no problem at the elementary school was "more detailed."

The DER press secretary saidtesting at East Penn was done at the request of the school superintendent. But in fact it was done at the request of state Rep. Don Snyder, R-134th District.

"They called us, said, 'We're coming in,' and we said that's fine," commented James Vater, director of management and personnel services at the district.

Yesterday Snyder said that last month he asked DER to test all schools in the Southern Lehigh, East Penn and Parkland districts. He said DER never responded to his request, but later he learned the state had done testing only in Southern Lehigh.

Snyder said DER wanted to do only that school district. It maintained East Penn schools are only on the fringe of the so-called radon belt which exists along the Reading Prong - a range of hills better known as South Mountain in this area. Four to six of East Penn's schools are located on the mountain or along its base.

Radon is created by the decay of uranium in soil along the Reading Prong - which runs from Berks through southern Lehigh and Northampton counties and dips into northern Bucks.

Yesterday Snyder complained, "There's been a real reluctance" by DER do anything about radon beyond Berks County - where it first began investigating the problem in January.

Dallas said DER plans to test up to 21,000 homes in the Reading Prong for radon within a year, adding that work will begin in July.

Dallas said, "It will probably be early summer at the earliest" before more homes or schools in Lehigh, Northampton or Bucks County are tested.

"We are really throwing everything we can into it and getting there as fast as we can, but we want it to be done right," said Dallas. "We must have the right kind of equipment, and we can't just hire people off the street. They must be qualified."

The press secretary said testingof schools will be DER's first priority, before it checks homes for radon. He said DER has an immediate responsibility for public buildings and immediate access. He also said young people might be at greater risk from radon, which can cause lung cancer, than adults.

When he found out Southern Lehigh was being tested, Snyder said he pleaded with DER to at least do East Penn schools also. The state legislator indicated he did not again press for testing of Parkland School District, which more clearly is beyond the Reading Prong, but felt he had an initial obligation to request testing for all three districts he represents.

Greene said Snyder asked DER to do testing of Southern Lehigh at his request, after a public hearing on radon was held in Southern Lehigh Middle School last month.

Late yesterday Snyder called Dallas to correct the information released by the DER press secretary yesterday afternoon.

Dallas said so far 1,745 homes have been tested by DER - all in Berks County. Radon levels which require steps to mitigate a potential health threat were found in 40 percent of those homes. Only one of the homes tested by DER so far had radon problems significant enough to require that it be evacuated.

Dallas said schools in southern Berks County also were tested for radon, but no problems were found.

He said DER already has spent a half-million dollars for radon testing, "not counting salaries." The department hopes more money to double its radiation protection staff will be included in the new state budget to be passed in July, so the testing can be completed within a year.